First Attempt for full navbar transparency in Trebuchet.

Reduced padding, modified a few methods so that
mWallpaperHack stays and also mWorkspace.isRenderingWallpaper
stay, but full transparency ended being dependent on
wallpaperScrolling being enabled (which is defaulted to true).

i commented a few lines for testing, once we test it i will
submit another patch to clean it up.

i also changed the default number of rows && columns for
phablet && tablet UIs so that icon and widgets remain in place
after changing UIs.

Change-Id: I270866af34f3edf6f7a4ccfe3af81915780122b7